Protective helmet



FIG. 1 is a right side view of a protective helmet showing my newdesign;

FIG. 2 is a left side view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

CLAIM The ornamental design for a protective helmet, as shown anddescribed.